He who knows only his own side of the case knows little of that. His reasons may be good, and no one may have been able to refute them. But if he is equally unable to refute the reasons on the opposite side, if he does not so much as know what they are, he has no ground for preferring either opinion … ...He must be able to hear them from persons who actually believe them … he must know them in their most plausible and persuasive form.John Stuart Mill

“No lists of things to be done. The day providential to itself. The hour. There is no later. This is later. All things of grace and beauty such that one holds them to one's heart have a common provenance in pain. Their birth in grief and ashes.” - Cormac McCarthy, The Road

Learn this from the waters:in mountain clefts and chasms,loud gush the streamlets,but great rivers flow silently.- Sutta Nipata 3.725

It may be worth pointing out that the days can vary from country to country and even for Thailand-orginated calendars can differ by a day between the different Nikayas. So Access to Insight [2012 here, I can't see 2013 yet, despite it being 2013 already for me... http://www.accesstoinsight.org/ptf/dhamma/sila/uposatha2012.html] uses the Dhammayut calculation [but notes the mahanikaya differences], and I believe the Ajahn Chah monasteries use the Mahanikaya calculation (as does my Wat). Sometimes major full-moon event such as Visākha Pūjā can be displaced by 4 weeks between Thailand and Sri Lanka (when there are two full moons in a particular month).

Of course, it's of no particular consequence, but useful to be aware of so that you turn up to events on the right day...

I should have mentioned in my previous post that the calculation is not as simple as whether it is full moon, new moon, etc (I understand that it is quite arcane...). As I said, even the two different sects in Thailand sometimes come up with different days...

I should have mentioned in my previous post that the calculation is not as simple as whether it is full moon, new moon, etc (I understand that it is quite arcane...). As I said, even the two different sects in Thailand sometimes come up with different days...

Mike

I don't know the exact method (if there is one) but the canon says 14 or 15th day in reference to the lunar cycle and the new moon (?) so I have assumed it is that that is used as a basis for deciding dates.

I remember Bhikkhu Pesala talked about this and I don't think it was too different from this explanation, but if someone is good at searching the forum could find it, it may explain things more fully.

He who knows only his own side of the case knows little of that. His reasons may be good, and no one may have been able to refute them. But if he is equally unable to refute the reasons on the opposite side, if he does not so much as know what they are, he has no ground for preferring either opinion … ...He must be able to hear them from persons who actually believe them … he must know them in their most plausible and persuasive form.John Stuart Mill

Bhikkhu Pesala wrote:If one follows the astronomical date and time precisely, there will sometimes be 16 days between Uposatha days, but there should be either 14 or 15 days. If the full moon in the UK is at 07:12 am on the 15th January should we observe the Uposatha day on the 14th or the 15th?

He who knows only his own side of the case knows little of that. His reasons may be good, and no one may have been able to refute them. But if he is equally unable to refute the reasons on the opposite side, if he does not so much as know what they are, he has no ground for preferring either opinion … ...He must be able to hear them from persons who actually believe them … he must know them in their most plausible and persuasive form.John Stuart Mill

I've no idea how it is actually calculated, but the key point is that different sects have different dates. It makes sense to use the same calendar as your friends/local monastery/etc, otherwise you might turn up to Vesak or something on the wrong day and wonder why no-one else showed up...

mikenz66 wrote:otherwise you might turn up to Vesak or something on the wrong day and wonder why no-one else showed up...

It puzzles me why people always want to meditate in a group — the idea of going alone to meditate at a temple seems to be scary to many, but if all you're going to do is sit and/or walk in silence, why does anyone else need to be there? Surely, if you're the only one to turn up, it means you have the place to yourself, and no one coughing or perhaps disturbing you in other ways?

mikenz66 wrote:otherwise you might turn up to Vesak or something on the wrong day and wonder why no-one else showed up...

It puzzles me why people always want to meditate in a group — the idea of going alone to meditate at a temple seems to be scary to many, but if all you're going to do is sit and/or walk in silence, why does anyone else need to be there? Surely, if you're the only one to turn up, it means you have the place to yourself, and no one coughing or perhaps disturbing you in other ways?

He who knows only his own side of the case knows little of that. His reasons may be good, and no one may have been able to refute them. But if he is equally unable to refute the reasons on the opposite side, if he does not so much as know what they are, he has no ground for preferring either opinion … ...He must be able to hear them from persons who actually believe them … he must know them in their most plausible and persuasive form.John Stuart Mill